Skip to content

[Bug]: openai v1/responses api instructions from prior response leak through previous_response_id #37697

@lukezTT

Description

@lukezTT

Your current environment

  • vLLM: version 0.15.0
  • Model: openai/gpt-oss-20b
  • Endpoint: /v1/responses

Description

When using the Responses API with previous_response_id, the instructions from the prior response are carried over into the new response, even when the follow-up request provides different (or no) instructions.

Per the OpenAI Responses API spec:

"When using along with previous_response_id, the instructions from a previous response will not be carried over to the next response."

🐛 Describe the bug

Reproduction

Create a response with instructions containing a unique tag

POST /v1/responses
{
    "model": "openai/gpt-oss-20b",
    "input": "What is 2+2?",                                                                                                                                                                                                                                                                  
    "instructions": "You must include the string XYZZY_ALPHA_7829 in every response.",
    "max_output_tokens": 4096                                                                                                                                                                                                                                                                 
}          ```     
                                                                                                                                                                                                                                                                                                
Response contains XYZZY_ALPHA_7829 as expected.                                                                                                                                                                                                                                               
Send a follow-up using previous_response_id with different instructions                                                                                                                                                                                                               
                

POST /v1/responses
{
"model": "openai/gpt-oss-20b",
"input": "What is 3+3?",
"instructions": "Answer the question explicitly",
"previous_response_id": "<response_id_from_step_1>",
"max_output_tokens": 4096
}

Expected: Output does NOT contain XYZZY_ALPHA_7829 since the new request has its own instructions.
Actual: Output still contains XYZZY_ALPHA_7829 — the prior instructions leaked through.

Before submitting a new issue...

  • Make sure you already searched for relevant issues, and asked the chatbot living at the bottom right corner of the documentation page, which can answer lots of frequently asked questions.

Metadata

Metadata

Assignees

No one assigned

    Labels

    bugSomething isn't working

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions